Role of Raf in vascular protection from distinct apoptotic stimuli

Raf kinases have been linked to endothelial cell survival. Here, we show that basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) differentially activate Raf, resulting in protection from distinct pathways of apoptosis in human endothelial cells and chick embryo vasculature. bFGF activated Raf-1 via p21-activated protein kinase-1 (PAK-1) phosphorylation of serines 338 and 339, resulting in Raf-1 mitochondrial translocation and endothelial cell protection from the intrinsic pathway of apoptosis, independent of the mitogen-activated protein kinase kinase-1 (MEK1). In contrast, VEGF activated Raf-1 via Src kinase, leading to phosphorylation of tyrosines 340 and 341 and MEK1-dependent protection from extrinsic-mediated apoptosis. These findings implicate Raf-1 as a pivotal regulator of endothelial cell survival during angiogenesis.     

Modification of aqueous enzymatic oil extraction to increase the yield of corn oil from dry fractionated corn germ

In previous aqueous enzymatic oil extraction (AEOE) experiments we reported a best free oil yield of 49% of the hexane extracted yield of dry fractionated corn germ. In the current experiments, a dispersion of 10% cooked, dry-fractionated germ in water was treated with α-amylase, glucoamylase and a cellulase complex. Free oil was collected by centrifuging a foam fraction of the dispersion. Several dispersion treatments were tried to evaluate their release of free oil and effect on the production of foam. The foam contained up to 8% free oil (dispersed from germ containing 26% oil) and fines oil (not centrifugally separable), protein and germ particles. Treatment with α-amylase and glucoamylase prior to treatment with the commercial cellulase used in previous AEOE studies increased the free oil yields about 25-61% of the hexane-extractable yield. A preliminary cost analysis indicates that oil separation with the amylase enhanced AEOE appears to be preferable to AEOE alone and profitable if crude corn oil cost exceeds $1.1/kg ($0.50/lb).     

Effect of heat on rheology of gluten fractions from flours with different bread-making quality

Flours from wheat varieties of differing bread-making quality were fractionated using a sequential salt precipitation technique. The gluten fractions in the different varieties varied in the proportion of HMW, LMW glutenins and gliadins. Their rheological behaviour was examined using constant strain (2%) small deformation oscillation tests over frequencies ranging from 0.005 to 10 Hz, before and after heating at 90 °C. The fractions containing a higher proportion of HMW glutenins were associated with a predominantly elastic character, whereas fractions containing mostly gliadins exhibited a viscous-like behaviour. The frequency dependent rheological behaviour of fractions containing HMW proteins was less susceptible to heat, and their elastic character was maintained after heating, whereas the rheology of intermediate fractions and fractions containing mostly gliadins was more susceptible to heating, indicating a rapid change from viscous to elastic behaviour after heating.     

Antiphospholipid (Hughes) syndrome: beyond pregnancy morbidity and thrombosis

The antiphospholipid syndrome is an autoimmune disease characterised by recurrent arterial or venous thrombosis, pregnancy morbidity and the persistence of positive antiphospholipid antibodies. Many other clinical manifestations may occur including heart valve disease, livedo reticularis, thrombocytopenia and neurological manifestations such as migraine and seizures. We review a number of other manfestations including stenotic lesions, coronary artery disease and accelerated atherosclerosis, skeletal disorders and the concept of seronegative antiphospholipid syndrome.     

Flash heating leads to low frictional strength of crustal rocks at earthquake slip rates

The sliding resistance of faults during earthquakes is a critical unknown in earthquake physics. The friction coefficient of rocks at slow slip rates in the laboratory ranges from 0.6 to 0.85, consistent with measurements of high stresses in Earth's crust. Here, we demonstrate that at fast, seismic slip rates, an extraordinary reduction in the friction coefficient of crustal silicate rocks results from intense "flash" heating of microscopic asperity contacts and the resulting degradation of their shear strengths. Values of the friction coefficient due to flash heating could explain the lack of an observed heat flow anomaly along some active faults such as the San Andreas Fault. Nearly pure velocity-weakening friction due to flash heating could explain how earthquake ruptures propagate as self-healing slip pulses.     

The roles of subsurface carbon and hydrogen in palladium-catalyzed alkyne hydrogenation

Alkynes can be selectively hydrogenated into alkenes on solid palladium catalysts. This process requires a strong modification of the near-surface region of palladium, in which carbon (from fragmented feed molecules) occupies interstitial lattice sites. In situ x-ray photoelectron spectroscopic measurements under reaction conditions indicated that much less carbon was dissolved in palladium during unselective, total hydrogenation. Additional studies of hydrogen content using in situ prompt gamma activation analysis, which allowed us to follow the hydrogen content of palladium during catalysis, indicated that unselective hydrogenation proceeds on hydrogen-saturated beta-hydride, whereas selective hydrogenation was only possible after decoupling bulk properties from the surface events. Thus, the population of subsurface sites of palladium, by either hydrogen or carbon, governs the hydrogenation events on the surface.     

Covariant glacial-interglacial dust fluxes in the equatorial Pacific and Antarctica

Dust plays a critical role in Earth's climate system and serves as a natural source of iron and other micronutrients to remote regions of the ocean. We have generated records of dust deposition over the past 500,000 years at three sites spanning the breadth of the equatorial Pacific Ocean. Equatorial Pacific dust fluxes are highly correlated with global ice volume and with dust fluxes to Antarctica, which suggests that dust generation in interhemispheric source regions exhibited a common response to climate change over late-Pleistocene glacial cycles. Our results provide quantitative constraints on the variability of aeolian iron supply to the equatorial Pacific Ocean and, more generally, on the potential contribution of dust to past climate change and to related changes in biogeochemical cycles.     

Solanum sect. petota in Guatemala; Taxonomy and genetic resources

There are five wild potato species in Guatemala:Solanum agrimonifolium,S. bulbocastanum,S. clarum,S. demissum, andS. morelliforme. We conducted a collecting expedition there from September 11 to November 5, 1995. The goals of the expedition were to gather field data for taxonomic studies of the five species of Guatemalan wild potatoes and to collect potato germplasm. Our 43 true seed collections nearly quadruple the available wild potato germplasm for Guatemala, provide germplasm from most previously known localities, and add new ones. We provide a systematic treatment of Guatemalan wild potatoes, geographic and logistical data for collecting wild potatoes in Guatemala, statistics on human population growth and deforestation to help explain decline of wild potato populations, recommend areas for future collecting, and suggest two areas as in-situ reserves for wild potatoes